Drugs that act directly on the renin-angiotensin system can cause fetal and neonatal morbidity and death when administered during pregnancy. A committee of the National Institutes of Health has recommended that these drugs be avoided during pregnancy. Limited data have shown an association between major congenital malformations and the use of ACE inhibitors during the first trimester. In addition, the use of drugs that act directly on the renin-angiotensin system during the second and third trimesters of pregnancy has been associated with fetal and neonatal injury, including hypotension, neonatal skull hypoplasia, anuria, reversible or irreversible renal failure, and death. Oligohydramnios has also been reported, presumably resulting from decreased fetal limb contractures, craniofacial deformation, and hypoplastic lung development. Prematurity, intrauterine growth retardation, and patent ductus arteriosus have also been reported, although it is not clear whether these occurrences were due to exposure to the drug. Mothers whose embryos and fetuses are exposed to an ACE inhibitor during the first trimester should be informed of the risks. When pregnancy is detected or expected, quinapril should be discontinued as soon as possible.

Quinapril has been assigned to pregnancy category D by the FDA for use during the second and third trimesters and to category C during the first trimester. Animal and human data have revealed evidence of embryolethality and teratogenicity associated with ACE inhibitors. There are no controlled data in human pregnancy. Congenital malformations have been reported with the use of ACE inhibitors during the first trimester of pregnancy, while fetal and neonatal toxicity, death, and congenital anomalies have been reported with the use of ACE inhibitors during the second and third trimesters of pregnancy. If the patient becomes pregnant, quinapril should be discontinued as soon as possible. Quinapril is considered contraindicated during pregnancy.